Will tropical coral reefs be the first ecosystem to be eliminated by climate change?

Saturday, September 02, 2006

ReefVid

Apologies to those for whom this is old news (I only caught up thanks to the Netwatch section in Science), but Peter Mumby has put a collection of video footage online at Reefvid.org. There's a lot here that is beautiful and instructive.

There is a forlorn hope that spraying 7 billion tonnes per year of fossil carbon (in the form of carbon dioxide (CO2)) from the combustion of coal, oil and gas into the atmosphere will have little impact on the chemical structure of the atmosphere and the oceans. Sadly, this is not the case. Since the industrial revolution, the proportion of carbon dioxide in the atmosphere has increased from 250 parts per million (ppm) to todays value of 380 ppm. By the middle of the 21st century, this is likely to increase to 750 ppm – a ‘tipping point’ being investigated by EPOCA (the European Project on Ocean Acidification). Why EPOCA ??

The GAIA Theory - Professor James Lovelock has put forward the GAIA theory – in essence this proposes a linkage and interactivity between oceans, the atmosphere, ice, volcanoes and land masses and their populations. This linkage is starting to show in the interaction and exchange of gases between the atmosphere and the oceans. Oceanic phytoplankton are responsible for absorbing about 50% of the atmospheric CO2 and releasing some 50% of oxygen being fed into the atmosphere. The absorption results in a progressive ‘acidification’ (carbonic acid) of the chemical make-up of the seas. The result has similarities to the atmosphere – the pH value (alkalinity) level of the oceans has dropped from a value of 8.2 to 8.0 over the period since the start of the industrial revolution. Whilst the GAIA theory suggests a level of ‘self-regulation’ between interactivity, it does not preclude change.

Phytoplankton and Zooplankton

Phytoplankton Phytoplankton are the most important organisms in the marine food chain in that, through a process of photosynthesis, they combine the inorganic elements of seawater, CO2 and sunlight to form the organic ‘vegetable matter’ (including algae) at the base of the marine food chain. This same photosynthetic process releases the oxygen into the atmosphere.

Zooplankton. Zooplankton are equally important to the marine food chain in that they extract calcium from the calcium carbonate dissolved in the oceans. This calcium reinforced protein (and the skeletal remains) forms the basis for the deposition of chalk (coral reefs and the white cliffs of Dover), limestone (the Dolomites and Mendips), the formation of coral reefs (via the coral polyps), the formation and development of shell coverings for lobsters. crabs, scallops and clams and, probably the skeleton formation for such species as the cod and haddock.

Climate The main ‘driver’ in climate change is water vapour (held in the atmosphere in a gaseous invisible form). The condensation of this water vapour (attaching to hygroscopic nuclei – man-made and naturally-occurring) on dust in the atmosphere creates visible cloud droplets which fall to the ground when sufficiently coalesced and heavy enough in the form of rain, sleet or snow. Warm air can hold more water vapour than cold air. This will mean that a warmer climate will mean less cloud formation, (with its attendant protection from direct sunlight) and a dryer earths surface (extending desert areas) - - the water vapour will be held in the atmosphere in the vapour form

Arctic and Antarctic Summer Sea Ice Melt The importance of plankton to various migratory whales and dolphins is shown by polar summer sea-ice melts. These melts release plankton trapped in the sea ice in trillions. These plankton are taken up by the krill which, in turn, is the food reward for whales and dolphins undertaking the migration.

Why should ocean acidification concern us ?? The importance of the impacts of progressive ocean acidification cannot be over-stated. There is very strong scientific evidence (to the point that DEFRA is charging the Plymouth Marine Laboratory and the National Oceanographic Institute with urgent research projects) that the calcification process including shell formation on most of the benthic (sea-bed dwelling) and skeletons on pelagic (surface water) species in UK waters is being inhibited by the acidification. Does this mean the end of crab sandwiches, lobster thermidor and cod and chips ?? Only more and very urgent scientific research can answer this one. The implications for the marine food supplies and the associated industries hinge on the findings of such research. The fact is that ocean acidification has serious social, economic, diplomatic, political, cultural and industrial implications on a global scale.

It seems likely that. by the middle of this century, only the more acid-tolerant species of marine life will survive in any healthy state.

The following is an extract from a letter received from DEFRA dated 3rd December 2008:

“ DEFRA recognises that ocean acidification will remain one of the most important environmental and societal concerns of the 21st Century and a driver, with climate change, for urgent and rapid reductions in CO2 emissions. There is an important requirement to understand better the effects of atmospheric CO2 increases on ocean acidification and the resulting impacts on marine life”.

Our response to this letter included a query on why the Marine and Coastal Access Bill (currently (15th Dec 08) going through its second reading in the House of Lords) did not contain the proposals on Carbon Capture and Storage (CCS) outlined in the White Paper for the Bill. It transpires that the CCS issue was transferred to the Energy Act which received royal assent on 28th November 2008. We have also respectfully suggested that research on the impact of ocean acidification on phytoplankton and zooplankton might deserve some high level of priority.

Shark depletion is another separate subject matter – effectively attacking the oceans from a ‘top-down’ perspective, rather than the acidification ‘bottom-up’ viewpoint. The removal of one grey reef shark is roughly the equivalent of removing the doctor, headmaster and refuse-collection service from a UK-based land parish for a period of 10 years. Imagine the outcry if this happened in the land-based environment !! With the price of shark fins imported through Hong Kong market now reaching £145.00/kilo (from £35.00/kilo some 6 years ago), it is not surprising that a large contributor to the depletion lies in the welcome increase in Far East living standards. This is a cultural, diplomatic and commercial issue and will need sensitive handling. The issue is progressively being managed with the ever-increasing awareness of the marine environmental damage that excessive shark depletion causes. Some optimism can be gained from the thought that rhinos have now become a protected species after the anthropogenic ravages of the ‘powdered rhino horn aphrodisiac’ era. It is high time that the same protection was afforded to the endangered shark species and the stakes may be considered even higher.

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"Mike", the world's first hydrogen bomb, vaporised Elugelap island and other parts of the Enewetak atoll on 1 November 1952. In the half century or so since then humans have destroyed around a quarter - some say a half - of all tropical coral reefs, which are one the world's richest and oldest ecosystems and provide vital benefits in over 100 countries. Will the rest be gone within another fifty years - or less? So what?

Please note that this blog is now pretty much 'on hold', with only occasional updates since January 2008. For notes on the Anthropocene extinction and what comes next see The Book of Barely Imagined Beings.